PSY 418

The Frayed Nerves Anxiety Scale (FNAS) is used to measure the anxiety level of people on a scale from 0 to 1000. Four 418 students were randomly chosen and given the FNAS before their second exam. Their scores were 700, 653, 740, and 707. We don't know what sigma is.

1. What is x bar?

2. What is the standard error of the mean?

3. What is the 95% confidence interval for x bar?

4. What is the 99% confidence interval for x bar?

5. What is the 80% confidence interval for x bar?


6. A TA for the 418 class states that the mean stress level of the class is 750. The professor is not so sure. Take the TA's belief as the null hypothesis. Remember, only four subjects were run.

a. State the null and alternative hypotheses

b. Is it significant with alpha equal to .05?

c. Is it significant with alpha equal to .01?

7. An American and a Englishman get in an argument over who is more boring: Canadians or Belgians (subsequently a Belgian and a Canadian get in an argument over the relative intelligence levels of the English and the Americans, but that is a different story). To resolve the debate, the American and the Englishman collect some data on Canadians and Belgians using the North Atlantic Boredom Scale (NABS). A high rating indicates a boring person.

The data for four Canadians is: 25, 5, 24, 14.

The data for four Belgians is: 31, 41, 22, 42

a. State the null and alternative hypothesis.

b. Do Canadians and Belgians differ significantly in their level of boringness (use alpha at .05)?

8. Each group member needs to find two citations (one reference for each project idea) from PsychInfo that will be useful for the introduction of the future paper.